Rotary blower, compressor, and exhauster



Aug. 24, 1948.

J. RODWAY ROTARY BLOWER, COMPRESSOR AND EXHAUSTER 2 Sheets-Sheet 1' Filed March 2, 1944 4 I iventor k.- a. Attorneys Aug. 24, 1948. J. RODWAY 2,447,961

ROTARY BLOWER, COMPRESSOR AND EXHAUS'I'ER Filed llaidh 2, 1944 2 sheets-Sheet 2 4 0 C) Q. Q 14 A ttorneys Patented Aug. 24, 1948 OFFICE Roman-BLOWER, COMPRESSOR, AND

. EXHAUSTER t J ohn ltodway, Lincoln, England Application March'2,1944, Serial Nu.5 24,'iis

In Great Britain April 29, 1943 1 Thisinventionrelatesto rotary blowers, com pressors. and exhausters of the kindin-which a rotor having a number of vanes mounted to slide radially therein is mounted'eccentrically within a stator. In machines of this type it is already knowntointerpose between the ends of the rotor and the. stator casing, non-rotatable flat rings or washers spring loaded againstthe ends of the rotor and and edges of the vanes to prevent risk of siezure when the temperaturerises and the present invention is particularly directed towards machines embodying that feature.

Inthe operation of blowers and exhausters of the construction above indicated it has been found that there is a tendency for wear caused by vane flutter when passing the inlet and exhaust ports to shorten the useful life of the machine and that there is also a disproportionate wear on the vane driving elements conducive to harsh running and due to the fact that the path traversed by the-roots of the vanes is not circular but slightly elliptical. The object of the present invention'is to overcome these disadvantages and'provide an improved construction Which'is smooth running under all conditions and wherein the working life is greatly increased by th wear on the cooperating parts being more evenly distributed.

According to the invention a rotary blower or exhauster having the general'construction above indicated is provided wherein the said spring loaded end plates carry cam rings which also cause the outward radial movement of the vanes, the said cam rings being freely mounted with respect to the rotor shaft and stator casing for the' pur pose of enabling-them to creep as the rotor operates.

According to the preferred form of the invention a 'rotaryblower or'exhauster of the type above referred to is provided having springloaded sealing plates disposed between the ends of the rotor and the stator and characterised by the provision of cam rings freely mounted around the rotor shaft to engage the inner edges of the vanes and having annular flanges engaging apertures formed. in the said sealing plates.

Reference will now be made to the accompanying drawings which illustrate a rotary blower or exhauster constructed according to the invention and in which:

Fig. 1 is a sectional elevation taken in the plane of the axis of rotation.

Fig. 2 is a cross sectional elevation taken on the line AA of Fig. 1.

Fig. 3 is a cross sectional elevation taken on z -Claims. (01. 230-452) l 2 the line B- -B of Fig. 1, with the rotary vanes omittedland Fig. 4 is an external view showing an end elevation.

In the construction illustrated, and referring first'to Figs. 1 and 2 the stator comprises a casing component I having a cylindrical internal surface and detachable end walls 2 and 3 which carry bearings for a rotatable shaft 4 which is disposed eccentrically to the axis of easing component i and carries the rotor. The rotor consists of a drum 5 within slots 6 of which are mounted radially movable vanes 1 which are adapted to cooperate with the internal surfaces of the casing in the known manner. The device is adapted to draw air through an inlet 8 and port 9 and to compress and exhaust the air through. a port i0 and outlet II, which outlet is formed within a foot i2 integral with component I of the casing and provided with flanged parts l3 by which the device as a whole is mounted in operative position.

The casing components I, 2 and 3 are secured together by bolts whose heads are shown at Iii and which pass throughthe endwalls'l! and 3 and through lugs 15 formedexternally on the central portion I.

Between the side edges of the vanes l and the end walls 2 and 3. of th casing are disposed sealing plates lfiwhich take the form of annular discs whose diameter is greater than that of the cylindrical interior of the casing l and whose outer edges enter freely into annular grooves l1 formed between end walls 2 and 3 and the edges of the casing component I. Thesealing plates 16 are prevented from rotating by means of locating pins ill of which each plate carries one which enters a recess l9 formed in each wall 2 and 3. plates l6 are spring-loaded, the springs 20 being located in recesses 2| and one in the recess l9. Preferably six springs are employed spaced equidistantly around the "end walls 2' and '3 which are formed externally-with bosses indicated at 22 in Fig. 4 to accommodate the recesses I 9 and 2i.

The radial outward movement of the vanes I is produced bycam. rings 23 disposed concentricallywithin the casing component I, which freely surround the rotor shaft 4 and extend axially int-o the respective ends of the rotor, and bear beneath the inner edges 24 of the vanes. The rings 23 are formed with flanges 25 which lie beyond the respective ends of the rotor and bear against the end walls 2 and 3 respectively and engage within the apertures in the sealing plates 16 (see Fig. 3). The rings 23 are freely mounted so that they can move in the direction The of rotation as the operation of the device proceeds. The rotor shaft 4 is mounted in ball bearings 26 and is provided with double acting oil seals 21 at its ends. The device is lubricated by oil introduced at 28 which passes through a filter 29 and from thence through passages 30 and 3| formed in the walls of casing members I, 2 and 3, the passages 3| leading the oil to the shaft bearings. Oil which enters the rotor space is exhausted with the compressed air through port and outlet H and may be returned from thence to an engine oil sump or the air may be passed through a separator before reaching the atmosphere.

In the operation of the device above described the plates [6 act as rotor sealing plates and the fact that the clearance between the vanes and the end plates can thereby be maintained small without risk of seizure when the temperature rises enables good performance at low speeds and cold starting to be obtained. The freedom of the cam rings 23 to creep serves to prevent indentation of their surfaces at any one particular point due to vane flutter when passing the inlet and exhaust ports and by distributing the wear in this manner the working life of the device is greatly increased. In operation, the path traversed by the roots or inner edges of the vanes I is not circular but forms an ellipse within which the circular cam rings 23 are situated. In order, therefore, that the cam rings can operate with the greatest eiiiciency their diameters should be made as near as possible that of the minor diameter of the said elliptical path as, otherwise, the wear on the cam rings tends to distort them out of true circular shape and harsh running results. In order to ensure that the cam rings are maintained central within the elliptical path traversed by the roots of the vanes, only a smaller running clearance is formed between the flange 25 of each cam ring and the edge of the aperture within the adjacent sealing plate l6.

Where, as in the construction illustrated, the machine is constructed to act as an exhauster for maintaining a pre-determined degree of vacuum in the reservoir of a servo brake unit, the stator casing component I is formed with an additional port 32 communicating with a short air admission passage 33 containing a seating for a ball valve 34 which is normally held closed by a spring 35.

The spring loadin of the ball valve 34 is adjusted so that whenever a pre-determined degree of vacuum is exceeded in the reservoir the atmospheric pressure causes the ball valve 34 to be unseated to admit air to the casing i, 2, 3 and the reservoir until the required conditions are re-established.

I claim:

1. A rotary blower or exhauster, comprising a casing constituting a stator having fluid inlet and outlet ports, a rotor mounted eccentrically within said stator, a plurality of vanes mounted to slide radially in said rotor and contacting the walls of the stator, sealing plates disposed respectively at the ends of said rotor and having apertures therein concentric with the stator, means for maintaining said sealing plates in yieldable contact with the end edges of said vanes, and cam rings each mounted concentrically within the stator casing and having a cylindrical portion extending into the respective end of the rotor and engaging beneath the inner edges of the vanes and an outer flanged portion whose surface makes contact with one end wall of the stator and whose periphery rotatably engages the edge of said concentric aperture in the adjacent sealing plate.

2. A rotary blower or exhauster, comprising a casing constituting a stator having fluid inlet and outlet ports, the stator having end walls provided with recesses a rotor having a shaft and bearings for mounting the rotor eccentrically within said stator, the rotor having radial slots and recesses extending axially into its respective ends and intersecting said slots, a plurality of vanes mounted to slide radially in said slots in the rotor and contacting the walls of the stator, the vanes having inner edges the end portions of which extend into said recesses, sealing plates disposed respectively at the ends of said rotor and having apertures therein formed concentrically of the stator casing, and of a greater diameter than the recesses in the respective ends of the rotor, a projection on the outer surface of each sealing plate and engaging the respective recess in the adjacent end wall of the stator to prevent rotation of said plate, springs housed in the recesses in the end walls of said stator for maintaining said sealing plates in continuous but yieldable contact with the end edges of said vanes, and cam rings mounted concentrically Within the stator casing, each of said cam rings having a cylindrical portion extending into the recess in the respective end of the rotor and engaging the end portions of the inner edges of the vanes extending into said recess, and an outer flanged portion whose surface makes contact with one end wall of the stator and whose periphery engages the edge of the aperture in theadjacent sealing plate JOHN RODWAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 582,696 Schneible et a1 May 18, 1897 1,321,340 Stoke Nov. 11, 1919 1,436,863 Crouse Nov, 28, 1922 1,539,728 Ensign May 26, 1925 1,996,875 McCann Apr. 9, 1935 2,264,616 Buckbee Dec. 2, 1941 2,312,655 Lauck Mar. 2, 1943 FOREIGN PATENTS Number Country Date 426,427 Great Britain Apr. 3, 1935 505,645 France May 11, 1920 606,765 France Mar. 13, 1926 

